Front and Rear Diff

[cymru]

Can someone tell me which oil to buy exactly.... that includes lubricants I have a 99 EB and it is 4wd with 10 bolts on the back at least which I guess means 9. Thank you in advance.... I am confusing the hell out of myself with all the shit on the internet. Price is not a problem I just want to keep this thing running forever. it has 70k on her yeah thats right 70k. I got a new cover for the rear so I want to change now obviously. Additionally, I want to start changing my own oil and I know the guy I take it to is not using syn. Which oil should I use? Weight? Mobile One like my Benz? Thanks in advance.... I am sure some of you know these exact answers.... love the board pics coming soon I am doing a ton of mods..

Evan from Joisy

 

[tonydiv]

Here's a laugh.... Ford says that the differentials are 'lubricated for life' and NEVER need servicing.

The exact specs and quantities for the lube are in the manual. I used full synthetic fluids in the diffs, transfer case and transmission. Just make sure that if you have the limited slip in the rear that you add the proper friction modifier.

 

[cymru]

Thats the issue I do not know if I have limited slip in the rear and I heard that if you use some of the higher end stuff you do not need to use the friction modifier. Any help on the weight would be great. The guys at autozone said one weight my stupid chiltons guide says another but it is for 150's 250's Navigators etc. I am sorry to be a pain but anyone with a 99 Eddie Bauer 4wd do this??? What exactly did you use. Thanks. Primarily focused on the rear.

 

[FordandPolaris]

Check the doortag for the axle code and then find the code here:

What rear end ratio is in my Ford , do I have positraction? - Drivetrain.com

They do not list axle code H6 for some reason, but if that is your code, it is a 3.73 LSD.

 

[djacobs]

the only motor oil I use is motorcraft 5w 20 synthetic sold at walmart and I use Valvoline 75w 90 in the differentials